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164 Cards in this Set
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STAPHYLOCOCCI |
Gram Positive cocci in grape like clusters Non-motile |
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Catalase Test (+) |
Presumptive test to differentiate staphylococci |
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Principle: |
H²O² is converted to water and oxygen by the presence of enzyme catalase |
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Reagent: |
3% H²O²- can be directly add to the culture media or in the slide; (+) Result: vigorous bubbling |
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NaCl |
Able to grow in 7.5-10% |
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Bacitracin |
Resistance to 0.2-0.4 units of Bacitracin |
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Pigment formation/ Growth on Leoffer's Serum Slant ( LSS ) |
- Staphylococcus aureur - golden yellow |
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Staphylococcus aureurs |
Golden yellow |
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Staphylococcus citreus |
Lemon yellow |
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Staphylococcus albus |
White |
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STAPHYLOCOCCUS AUREUS |
-Normal flora of anterior mares and nasopharyx -PCR will enable detection form nasal swab |
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GROWTH/COLONY MORPHOLOGY |
- Uniform turbidity on broth - Jet back colonies on tellurite agar |
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Test For Identification |
Catalase (+) Coagulase (+) Mannitol Fermentation (+) DNase Test (+) VP and Nitrate (+) |
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HEMOLYSIS ON BAP |
Beta-hemolytic |
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VIRULENCE FACTOR
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ENZYMES:
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Lipase |
Intiate skin infection |
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Hyluronidase |
Spreading factor; it enhances the invasion into the tissues |
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Beta lactamase/panicillinse |
Makes the S. aureus resistant to penicillin |
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Staphylokinase |
Promote fibrilysis ( dissolution of clot) |
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Coagulated |
It causes the bacterial cells to agglutinate in the plasma; it also coverts fibrinogen to fibrin |
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Beta-hemolysin |
Responsible for the B-hemolytic properly of S. aureus |
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Protein A |
Prevents phagocytosis |
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Virulence Factors |
Toxins: |
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Enterotoxin A and B |
Food poisoning |
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Enterotoxin F / TSST |
Causes the toxin Shock Syndrome |
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Exfoliation |
Epidemiologic TOXIN that causes desqumation ( or exfoliation) of the skin in scalded skin syndrome aka Ritter's disease |
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PLP / Planton Valentine Leucocidin |
Targets WBC, causing its destruction; associate with MRSA ( Methicillin-resistant S. aureur) infection |
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Causes |
»Boils, furuncles, carbuncles, folliculitis, cellulitis, wound infection |
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»Bullous impetigo |
Skin infection of epidermidis, involving epithelial cells |
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»TOXIC MEDIATED DISEASES: |
Food poisoning Toxic Shocks Syndrome Scalded Skin Syndrome |
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A. COAGULATION TEST
a.1' Slide Coagulase: |
For the detection of Clumping factor aka Bound Coagulase |
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Clumping factor |
Readily converts fibrinogen to fibrin which produces a clot |
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- Bacteria+NSS+rabbit plasma ( alternative: |
Plasma from EDTA) = fibrin clot |
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Notes: |
-if the test is (-) perform the tube coagulase -Citrated plasma can cause false (+) in this test |
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Positive (+) result |
S. aureus, S. lugdunensis and S. Schleiferi |
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a.2. Tube Coagulase |
To detect the free coagulase |
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Free coagulase |
Produce a clot only when incubated |
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Positive (+) result |
S. aureus |
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B. Mannitor Fermentation Test (+) |
Media: Mannitol Salt Agra ( MSA) |
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PH indicator: |
Phenol red |
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MONNITOL (+) |
Yellow/Pink |
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Staphylococcus |
-Only grow in medium with Hugh salt content -the agar from pink to yellow
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Colonies |
Identified by their yellow halo |
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S.aureus |
Has characteristics of an " old sock" odor in MSA |
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S.aureus |
Has characteristics of an " old sock" odor in MSA |
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DNase Test (+) DNase Test (+) DNase Test (+) DNase Test (+) DNase Test (+) |
Detect deoxyribonuclease |
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There are 2 methods: |
A.) DYE METHOD B.) HCI PRECIPITATION METHOD |
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A.) Dye Method |
Media: DNase agar * the dye should be incorporated first before inoculating the organism |
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1. DNA + methyl green |
Clear zone around the colonies |
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2.DNA + toluidine blue |
Observed pink around the colonies |
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B. HCI precipitation method |
Inoculate the organism in a plain DNase agar ->incubate->add HCl |
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(+) result |
Clearing of the media/around the colonies |
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Other DNase positive: |
S. Aureus Moraxella Serratia |
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Staphylococcus epidermidis |
CATALASE TEST = (+) COAGULASE TEST= (-) MaNNITOL FERMENTATION =(-) HEMOLYSIS ON BAP= gamma-hemolytic NOVOBIOCIN= S- more than 16 mm DNase TEST = (-) |
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Staphylococcus epidermidis |
OTHER -Normal skin flora - Causes UTI, stich abscess - prosthetic Heart Valve infection |
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Staphylococcus epidermidis |
VIRULENCE FACTOR - Known to its agility for smile production or biofilm formation - it enhances the attachment of the organism to plastic catheters
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STAHYLOCOCCUS SAPROPHYTICUS |
CATALASE TEST = (+) COAGULASE TEST= (-) MaNNITOLFERMENTATION =(-)HEMOLYSIS ON BAP= gamma-hemolyticNOVOBIOCIN= R-less than 16 mmDNase TEST = (-) |
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STAHYLOCOCCUS SAPROPHYTICUS |
OTHERS: - Most common cause of UTI in (sexually active) young females - causes pyelonephritis and cystitis in those with indwelling catheters |
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VIRULENCE FACTOR |
Lipoteichpic acid- a surface-associated portion that adheres urothelial cells Hemolysin- A hemagglutinin that bonds to fibronectin
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Novobiocin Susceptibility |
-differential susceptibility test for CONS |
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STOMATOCOCCUS MUCILANGINOSUS |
Now "ROTHIA" -Emerging pathologen for the immunocompromised patients; it can cause endocarditis and bacteremia -Weak Catalase (+) =Coagulase (-) ; =5% NaCl (-) =Capsule (+) |
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STOMATOCOCCUS INTERMEDIUS |
COAGULASE (-) VP (-) PYR (+) (+) - rare cause of human infection
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STOMATOCOCCUS lugdunensis |
Slide coagulase (+) Mannitol(+) Narrow B-hemolytic PYR (+) -Cause endocarditis and bacteremia |
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MICROCOCCI
Micrococcus luteus |
Gram (+) cocci in TETRADS; stick aeroble (an Oxidizer) |
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On BAP |
Gamma-hemolytic |
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Modified Oxidase Test |
Presumptive test intended to identify Micrococci |
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BLUE COLOR |
Use tetramethyl |
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STAPHYLOCOCCUS |
Aerobic= + Anaerobic growth = + Lysostaphin Susceptibility= S Modefied Oxidase Test = - Bascitracin susceptibility = R
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STAPHYLOCOCCUS |
Furazolidone/ Furoxone Susceptibility = R Catalase Test = + Benzidine Test = - Glucose Utilizatin / of medium = fenmenter |
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Micrococcus |
Aerobic= + Anaerobic growth = - Lysostaphin Susceptibility= R Modefied Oxidase Test = + Bascitracin susceptibility = S |
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Micrococcus |
Furazolidone/ Furoxone Susceptibility = S Catalase Test = + Benzidine Test = + Glucose Utilizatin / of medium = Oxidizer |
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STREPTOCOCCI |
»Gram (+) cocci in chain, spherical to avoid |
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Non-motile |
Capnophilic ( 5-10% CO²) |
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Medium of Choice |
» 5% Sheep Blood agar |
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Selective medium |
»Phenyl Ethyl Alcohol (PEA) agar |
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A.) Smith and Brown Classification |
»based on the hemolytic pattern of the organism |
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Smith and Brown Classification |
1.) Alpha hemolytic Streptococci 2.) Beta hemlytic Streptococci 3.) Gamma hemlytic Streptococci |
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Alpha hemolytic Streptococci |
Incomplete/partial hemolysis on BAP causing the greening of the agar |
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Alpha hemolytic Streptococci |
Streptococcus pneumoniae Viridans Streptococci-S. Mitis and mutans
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Beta hemlytic Streptococci |
Complete hydrolysis showing clear zones around the colony |
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Beta hemlytic Streptococci |
*Steptococcus pyogenes *Steptococcus agalactiae |
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Gamma hemlytic Streptococci |
Unable to cause hemolysis on BAP I,e E. faecalis, S. bovis |
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Alpha Prime |
When a colony is sorrounded by an inner alpha and router beta zone. This may occur due to prolonged refrigeration |
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B.) Academic or Bergey's Classification |
Based on the physiological needs of the organism |
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Academic or Bergey's Classification: |
* Pyogenic *Viridans *Entercocci *Lactic group |
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1.) Pyogenic |
= (-) 10 and 45°C but (+) in 37°C i,e. S. pyogenes |
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2.) Viridans |
=(+) 45°C but (-) in 10°C i,e. S.mitis, S. mutans. S. sanguis, S. salivarious, S. Constellations S. intermedius |
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3.) Entercocci |
= (+) 10 and 45°C i,e. E.faecalis |
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4.) Lactin group |
=(+) 10°C but (-) in 45°C i,e. S.lactis S. cremoris |
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C.) Lancefield Classification |
Based on the extraction of C Carbohydrate from Steptococcal cell wall All streptococci EXCEPT *Viridans *S. peumoniae are placed under Lancefield |
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STEPTOCOCCUS PYOGENES |
*Growth/colony Morphology *Test for Identification and Susceptibility test *Virulence Factors *Causes |
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Growth/colony Morphology |
Best isolated on BAP, addition of SXT can enhance its recovery from heavily contaminated specimens |
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Test for Identification and Susceptibility test |
*Susceptible in bacitracin (0.02-0.04 units) *PYR positive *Catalase negative *Resistance to SXT |
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Virulence Factors: |
*Steptolysis *Erthrogenic/Pyogenic Toxin *Hyaluronidase/ Steptokibse *M protein *Protein F |
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Steptolysis |
Responsible for the β- hemolytic production of S. pyogenes |
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Steptolysis |
*Steptolysis O *Steptolysis S |
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Steptolysis O |
-O liable; antigenic-once released, it stimulated production of anti-Streptolysin O.
-Cause sub-surface hemolysis on BAP- can causes hemolysis only when incubated anaerobically |
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Steptolysis S |
-O² stable; Non-antigenic: can cause surface hemolysis on BAP |
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Erthrogenic/Pyogenic Toxin |
Causes rashes in Scartel Fever |
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Hyaluronidase/ Steptokibse |
Spreading factor; it enhances invasion to the tissues; promotes fibrinolysis |
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M- Protein |
Most important factor,it prevents phagocytosis- adheres to mucosal cells; interferes compliment activation |
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Protein F |
Facilitates attachment to host cells |
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Causes |
* Pharyngitis/ step throat *Erysipelas *Scarlet Fever *Necrotizing fasciitis *POST SEQUELAE |
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Erysipelas |
Skin infection |
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Scarlet Fever |
a form of pharyngitis with rashes
"Strawberry tongue"- manifestation of scarlet fever |
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Necrotizing fasciitis |
Rapid progressing skin infection |
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POST SEQUELAE |
If a pyogenic infection is left untreated for 1-3 weeks, patient will develop a post-streptococcal sequelae of Acute Rheumatic fever (AGF) or Acute Glomerulonephritis (AGN) / Bright's disease, experiencing repeated episodes of pharyngitis |
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Pyrrolidonyl Aminopeptidase Test |
*Principle *Reagent *Result |
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Principle: |
The enzyme L- pyrrolidonyl arylamidase hydrolyzes the L-pyrrolidonyl-β-naphthylamide substrate to produce a β-naphthylamine |
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Reagent: |
P-dimethylaminocinnamadehyde- detects the β-monoamine end product |
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(+) result |
Red color |
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(-) result: |
Organge or no.color change |
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(+) for PYR Test |
Group D- Enterococci and Group a Streptococci |
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Diagnosis test for Scarlet Fever: |
*Dick's test *Schultz-Charlton Test/ Blqnche phenomenon |
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Dick's test |
Susceptibility test for Scarlet Fever to determine if the person is at risk of developing the infection |
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(+) result: |
Redness at the sites of infection |
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Schultz-Charlton Test/ Blqnche phenomenon |
-Test to determine if the rashes is caused by Scarlet Fever or not -injecting anti-erthrogenic toxin |
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(+) Result: |
Fading/ fradual disappearance of rashes |
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2. Group B Streptococci- Streptococcus agalactiae |
*Causes *Test for Presumptive Identification |
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Causes |
-Septecemia,#1 Cause of NEONATAL MENINGITIS in infants -in adults: POSTPARTUM ENDOMETRIOSIS/ postpartum fever |
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Test for Presumptive Identification |
*Christie,Atkins,Munch,Petersen/ CAMP test (+) * Hippurate Hydrolysis test (+) *Resident to Bacitracin aka Taxo-A |
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Media: |
Blood agar |
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Known organism: |
S. aureus |
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(+) result: |
Enhance hemolysis as shown by arrow head zone of β- |
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Hemolysis; |
(-) result: no enhance hemolysis |
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What is CAMP FACTOR? |
-It is diffusible extracellular hemolytic protein that can act synergistically with beta-lysin of Staphylococcus aureus producing enhanced hemolysis |
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Hippurate Hydrolysis test (+) |
-Detects hydrolysis of sodium hippurate into benzoic acid and glycine the positive result is due to enzyme Hippurase/Hippurate hydrolysis -Benzoic acid is detected by FeCl while Glycine is usually detected by ninhydrin reagent |
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3. Group C steptococci |
There are animal pathogens, may cause severe pharyngitis followed by bacteremia, may also cause pneumoniae, cellulites and abscess |
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Group C steptococci |
S. equisimilis S. equi S. escalator S. zooepidemicus |
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Group F |
S. angnisus-can cause cellulites |
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Group G |
Usually found as normal flora of human GIT, vaginal tract and oropharynx |
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4.) Group D streptococci ( Group D- Non-Enterococci) / S. Bovis group |
*S. bovis and S. equines *Growth inhibited in 6.5% NaCl *Penicillin Sensitivite, Vancomycin Resistant *PYR Test (-), Bile Esculin(+)
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Cause UTI |
Endocarditis and septicemia; its isolation in the blood may be an indicative of colon cancer |
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Enterococci ( E. Faecalis, E. faecium, E. Durand, E. avium) |
*Normal GUT,GIT, and RT flora; common I TO among hospitalized patients *Grows in 6.5% NaCl *Penicillin and Cephalosporin Resistant *Bacitracin Resistant |
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Enterococci ( E. Faecalis, E. faecium, E. Durand, E. avium) |
*Bile Esculin and PYR Test positive *Hippurate hydrolysis(-) *Most common enterococcus isolated from human infection: E. Faecalis |
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Bile Esculin Test |
Presumptive Identification of Enterococci and Non-enterococci |
*Uses 40% bile *Media: Bile Esculin Media *Reagent/Indicator:Ferric ammonium citrate *Positive result: Blackening |
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BILE ESCULIN |
Enterococcus= + D-Non Enterococcus= + |
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Growth in 6.5% NaCl |
Enterococcus= + D-Non Enterococcus= - |
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PYR |
Enterococcus= + D-Non Enterococcus= - |
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Bite solubility Test |
For the identification of pneumococci |
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(+) result if on broth |
Cleaning of Media |
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In plated media |
BAP with suspected colonies-> add desoxycholate directly to the colonies->incubate at 35-27°C in 30 minutes |
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(+) result: |
Disintegration/ Lysis of colonies |
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Susceptible to Optochin (more than 14 mm zone) |
Test that will differentiate Pneumococci from other alpha hemolysis Steptococci- use TAXO P |
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Francis Test |
Skin test for pneumonia |
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PNEUMOCOCCI |
»Bile Solubility= + »Inulin Fermentation = Ferment inulin »Capsular Swelling= + »Quinidine and Optochin= Sensitive
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STREPTOCOCCI |
»Bile Solubility= - »Inulin Fermentation = Does not Ferment inulin »Capsular Swelling= - »Quinidine and Optochin= Resistant |
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Viridans Streptococci |
*Not classified under Dangerfield *Optochin RESISTANT *Bile insoluble *Normal floral URT, GIT and GUT *On BAP- alpha-hemolytic |
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Species: |
1.) Streptococcus mitis 2.) Streptococcus salivarus 3.) Streptococcus anguish causes subacute bacteria endocarditis (like the HACEK group) 4.) Streptococcus mutans causes dental cavity and dental plague
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Beta-Hemolytic Streptococci |
*Bacitracin *SXT (Trimethoprin/sulfamethoxazole *CAMP *PYR |
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Groups A |
*Bacitracin = S*SXT (Trimethoprin/sulfamethoxazole= R *CAMP= - *PYR= + |
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GROUP B |
*Bacitracin= R *SXT (Trimethoprin/sulfamethoxazole= R *CAMP= + *PYR = - |
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GROUP C, F,G |
*Bacitracin= R *SXT (Trimethoprin/sulfamethoxazole= S *CAMP= - *PYR= - |
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Hemolytic Pattern: |
*Alpa *Beta *Gamma |
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Alpha |
Viridans and S. pneumonie |
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Beta |
Group A, B, C and some Group D (Lancefield) |
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Gamma |
Mostly Group D |
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Miller Streptococci Complex |
Known to cause liver,spleen and brain abscesses |
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Miller Streptococci Complex |
*Colonies *Species |
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Colonies: |
"Caramel"/ " butterfly scotch" odor |
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Species: |
S. constellatus, S. intetermedium, S. anginosus |
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Nutritionally variant Streptococci Abiotrophia |
*AKA Thiol-requiring streptococci/ Pyridoxal Streptococci/ Sateiliting Streptococci *These are S. Adjacens and S. Detectives *When mixed with S. aureus they satellite around the colonies of S. aureus |
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Other Gram (+), Catalase (-) organisms isolated from Clinical Specimens ( that can cause infection in immunocompromised): |
*Pediococcus *Lactococcus *Leuconostos *Aerococcus *Rothia |
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Leuconostoc |
Both: (Histopathology) use as an adhesive in exfoliative cytology, low virulence potential |
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